First of all you cannot just to one thing and stop this offense schematically. However here is a brief summary of what I'd do if I faced the Pats 3 WR set, with a TE and Single RB.
1. Ditka is right. You take your physical safeties and "invert" them. Put them up on the 2 WRs and have them play a tough man to man in the short zones. You have your athletic CBs covering the 2 halfs of the field deep.
2. On the the LOS you play a 4 man front with 2 LBs (similar to what the Pats played against the Colts) and dare the offense to run the ball. This assumes you have a very good DL and LBs who can both cover and play the run.
3. You put a CB or Saftey on Welker in the slot and double him with the LB to Welker's side. In other words the Saftey plays a tough physical man to man favoring the outside cuts, and the LB looks for him on the inside cuts.
Its certainly not perfect, and has obvious holes as most defenses do, but you force the Pats to throw to their TEs and RBs rather their WRs. You force them to run the ball, rather than throw. You have to put pressure on the QB with 4 man rushes. You have to disguise this look. Make Brady look for his 4th and 5th options
In conjunction with this, you mix it up with some 5 man under coverages, which kills the short passing game the Pats love so much, and some 4 man unders with 3 over, to kill the long placing game.
You have to get pressure with just 4 men rushing though changing up which 4 you rush can bring dividends
Hey I didn't say it would stop the pats, but it would change the way they move the ball down the field, and perhaps slow them down. Making them make long 12+ play drives. Drives that could break because of errors and penalties.
JMHO